Under that logic, I would assume that a character with little to no strength bonus and trained equally with both standard and recoilless assault rifles should actually have less problem firing the recoilless weapon (resulting in greater OB) - which, unless I am missing something, is not the case unless they are firing bursts - in which case an agile guy can fire a heavy recoil weapon equally well to a strong character.
My expectation would be - Strength bonus can cancel out recoil impact, but would grant no extra bonus beyond that. OB Bonus would be best handled strictly by Agility or maybe even Agility + one of the more non-physical stats (Insight, Reasoning, or Self-Discipline).
Maybe I'll spin off something on that thought process...